The new software is built on feedback Sony received from the initiative launched earlier this year. If you want in, you'll have to check in with the Concept Sign-up app. It's first come, first serve so there's an element of urgency.
Note that the test is limited to select European countries: Sweden, Denmark, Norway, Finland, Iceland, Estonia, Latvia, Lithuania, United Kingdom, Ireland or Germany.
If you're selected for the test, you'll get a notification in the next few weeks. The software should start rolling out soon after that.
Sony plans to update the Z3 family (including the Tablet Compact), the Xperia Z2 and Z2 Tablet and several other devices to Android 6.0 Marshmallow.
Mistake in the text, not available in finland. Would've loved to test it :/
Actually LG have stated that LG G3 and G4 will upgrade to marshmallow, there's even been pictures of a G2 running marshmallow
Actually its the carrier that has to sign off on marshmallow NOT sony